Electrospinning is an atomization process whereby the interactions between an electrostatic field and a fluid are exploited to form nanoscale and microscale polymer fibers. These fibers can be collected as an interconnected web containing relatively thin fibers. Porous films resulting from these fibers have very large surface area to volume ratios, high permeability and small pore size that make them appropriate for a wide range of applications. Therefore these films are considered to be an ideal media to fix or encapsulate bacteria.
Earlier attempts to encapsulate microbes in nanofibers have been made by electrospinning various polymers. See for example, Salalha et al., Nanotechnology 17, 4675-4681 (2006); and Gensheimer et al., Advanced Materials 19, 2480-2482 (2007).
The previous attempts typically involved bulk immobilization in gels. Either the microbe did not survive or if it did the thick bulk polymer lacked porosity and was not easy to work with due to its thickness. When encapsulation via electrospinning was attempted, either, the microbe did not survive the process of encapsulation; or, if the microbe did survive, the final material was soluble in aqueous solution. A water soluble biohybrid material has minimal use since an aqueous environment would lead to disintegration of the material, thereby releasing the microbes. Therefore, these previous attempts to create useful encapsulated microbes produced materials having little practical value.
Thus there is a need for a process whereby bio-hybrid/bio-functional materials encapsulating microbes can be reliably formed while preserving the viability of the microbes, and wherein the final material is insoluble in aqueous solution.